HDPE‑EVOH Double‑Wall Composite Pipe, Coil & Straight Pipe Multiple Specifications | Vohon Petrochemical Solution Provider
HDPE‑EVOH double‑wall composite pipe is a high‑performance thermoplastic piping product specially developed for underground fuel transmission systems of gas stations. It adopts multi‑layer co‑extrusion forming technology, taking high‑density polyethylene as inner and outer structural layers and EVOH as the core hydrocarbon barrier layer. The product is supplied in two main forms: coil pipe for long‑distance continuous laying and straight pipe for segmented layout, covering multiple caliber specifications to adapt to new‑station construction and old‑station renovation projects. It is widely applied in fuel delivery pipelines, vapor recovery pipelines and tank‑to‑dispenser connecting pipelines. Buried fuel pipelines suffer complex service conditions including soil corrosion, stray current, ground settlement and long‑term contact with hydrocarbon fuels. Therefore, the piping system puts forward strict requirements on hydrocarbon permeation resistance, mechanical impact strength, underground anti‑aging performance, connection reliability and multi‑specification project adaptability.
Traditional piping materials have obvious deficiencies in gas station buried fuel pipeline projects. Carbon steel pipe owns high mechanical strength, yet it is susceptible to underground electrochemical corrosion. Once the anti‑corrosion coating is damaged during transportation and construction, rust, pitting corrosion and medium leakage will occur, which requires regular anti‑corrosion maintenance and brings high full‑life‑cycle cost. Single‑layer HDPE pipe gets rid of metal corrosion risks, but lacks effective barrier structure. Long‑term fuel permeation will lead to gasoline volatile loss and hidden soil pollution hazards. Ordinary composite pipes without EVOH barrier layer cannot meet the strict anti‑permeation standards of modern gas station projects. Besides, inferior plastic pipes may produce concealed leakage defects at joints after burial due to poor fusion connection quality, bringing great difficulties for later inspection and repair.
This HDPE‑EVOH double‑wall composite pipe is manufactured by precise multi‑layer co‑extrusion process. The outer HDPE layer delivers outstanding wear‑resistance, anti‑aging performance and stress‑resistance against surrounding soil, adapting to various complex underground burial environments. The inner HDPE layer resists swelling and erosion from liquid fuel. The sandwiched EVOH functional layer acts as a high‑efficiency barrier to hydrocarbon molecule penetration, effectively restraining fuel permeation and volatile loss. Coil‑type pipes reduce intermediate joints for long‑distance laying and lower leakage risks of connection points. Straight‑type pipes are flexible for short‑distance and segmented pipeline arrangement, matching diversified on‑site layout demands.
The whole series supports electro‑fusion connection with matched fittings. Under standardized construction, electro‑fusion joints form integrated sealing interfaces and greatly reduce leakage hidden dangers at connection positions. Favored by good flexibility, the pipe can tolerate slight ground settlement and foundation deformation without brittle fracture. Different from steel pipelines, this composite pipe requires no anti‑corrosion coating or cathodic protection, simplifying construction procedures and cutting later‑stage maintenance workload. Complete supporting accessories are available, including electro‑fusion couplings, elbows, tees and transition joints, to build a full‑set underground fuel piping network.
Vohon Petrochemical provides both coil and straight‑pipe products with multiple optional specifications. Custom dimensions can be offered according to project flow demand, burial depth, pipeline route and site layout. All products go through strict production inspection before delivery. The integrated skid‑mounted delivery mode facilitates loading and transportation. On‑site construction volume is moderate, which shortens project implementation cycle and minimizes interference with daily operation of gas stations.
All pipe bodies and matched fittings are designed in compliance with international station piping standards. Raw‑material formula is optimized for underground long‑term service, ensuring stable barrier performance and mechanical property. Complete technical documents such as material certificates and construction guidance manuals are provided.